The right response to a "magic trick" is to try to learn how the trick works, not go around for the rest of one's life assuming strangers can always pick out the ace of spades.

Here is a trivial model of the "trick" being fool-proof (and I do mean "fool" literally), which I believe has been discussed here a time or ten. Omega runs a perfect simulation of you, terminates it right after you make your selection or if you refuse to choose (he is a mean one), checks what it outputs, uses it to place money in the boxes. Omega won't even offer the real you the game if you are one of those stubborn non-choosers. The termination clause is to prevent you from enjoying the spoils in case YOU are that simulation, so only the "real you" will know if he won or not. And to avoid any basilisk-like acausal trade. He is not that mean.

EDIT: if you think that the termination is a cruel cold-blooded murder, note that you do that all the time when evaluating what other people would do, then stop thinking about it, once you have your answer. The only difference is the fidelity level. If you don't require 100% accuracy, you don't need a perfect simulation.